Information processing device, information processing method, and program

ABSTRACT

Improvement of use efficiency of radio resources is realizable. 
     An information processing device is an information processing device which includes a reception unit and a control unit. The reception unit included in this information processing device is a reception unit which receives a packet. In addition, the control unit included in the information processing device is a control unit which controls a packet monitoring state of the information processing device in case of detection of reception of a packet not addressed to the information processing device. The packet monitoring state is controlled on the basis of reception power at the time of reception of the packet not addressed to the information processing device.

TECHNICAL FIELD

The present technology relates to an information processing device. Morespecifically, the present technology relates to an informationprocessing device and an information processing method used forinformation exchange via wireless communication, and a program underwhich a computer executes this method.

BACKGROUND ART

There has been a wireless communication technology used for informationexchange via wireless communication. For example, there has beenproposed a communication method used for information exchange betweeninformation processing devices via a wireless local area network (LAN).

There has also been proposed an error detection method which detectswhether or not received packet data contains an error. For example, anerror detection method which detects an error by utilizing cyclicredundancy check (CRC) has been proposed. In case of detection of anerror in a received packet, for example, the received packet isdiscarded. In case of detection of no error in a received packet, it isfurther determined whether or not the received packet has been addressedto an own-device which has received the packet. Then, in case ofdetermination that the received packet has not been addressed to theown-device, the packet is discarded even if the packet has correctcontents.

This error detection method requires demodulation of an entire packet upto a final part. In this case, the presence or absence of an error indata is determined after reception of the final part of the packet.Accordingly, even incase of an error contained in a media access control(MAC) header, or a packet containing no error in the MAC header but notaddressed to the own-device, for example, error determination is madeonly after reception of the entire packet.

For overcoming this problem, there has been proposed a wireless packetcommunication system which additionally includes a field at an end of aheader for protocol in a layer higher than a physical layer within apacket to store an error detection code for the header in the additionalfield, for example (e.g. see Patent Document 1).

In addition, Basic Service Set (BSS) Color has been introduced byInstitute of Electrical and Electronic Engineers (IEEE) 802.11ah. ThisBSS Color may be used to determine the presence or absence of apossibility that a packet has been addressed to the own-device.

Furthermore, Dynamic Spectrum Sensing (DSC) technology has been proposedas a technology capable of improving use efficiency of radio resources(for example, see Patent Document 2).

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-261462

Patent Document 2: U.S. Pat. No. 5,553,316

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The conventional technology described above requires an additional fieldfor storing an error detection code. Moreover, a wireless communicationdevice unable to recognize the additional field may not correctlydemodulate a received frame.

On the other hand, according to a method using BSS Color, for example,determination that packets have not been addressed to an own-device ismade before reception of an entire packet. In this case, receptionopportunities may increase in a period of a process for receiving aremaining part of the packet, for example. It is important to improveuse efficiency of radio resources by increasing reception opportunities.

The present technology has been developed in consideration of thesecircumstances. It is an object of the present technology to improve useefficiency of radio resources.

Solutions to Problems

The present technology has been developed to solve the aforementionedproblems. A first aspect of the present technology is directed to aninformation processing device, an information processing method for theinformation processing device, and a program under which a computerexecutes this method. The information processing device includes areception unit that receives a packet, and a control unit that controlsa packet monitoring state in case of detection of reception of a packetnot addressed to the information processing device, the packetmonitoring state being controlled on the basis of reception power of thepacket. This configuration produces an effect of controlling the packetmonitoring state in case of detection of reception of the packet notaddressed to the information processing device. The packet monitoringstate is controlled on the basis of reception power of the packet.

In addition, according to the first aspect, the control unit may controlthe packet monitoring state on the basis of a comparison result betweenthe reception power of the packet not addressed to the informationprocessing device and a predetermined threshold. This configurationproduces an effect of controlling the packet monitoring state on thebasis of the comparison result between the reception power of the packetnot addressed to the information processing device and the predeterminedthreshold.

In addition, according to the first aspect, the control unit maydetermine the threshold on the basis of reception power of a referencesignal received from a first device that transmits a packet addressed tothe information processing device. This configuration produces an effectof determining the threshold on the basis of reception power of thereference signal received from the first device that transmits thepacket addressed to the information processing device.

In addition, according to the first aspect, the control unit maydetermine the threshold by using a latest reference signal included inreference signals received from the first device, or a plurality ofreference signals received from the first device. This configurationproduces an effect of determining the threshold by using a latestreference signal included in reference signals received from the firstdevice, or a plurality of reference signals received from the firstdevice.

In addition, according to the first aspect, the control unit maydetermine the threshold by using a reference signal that has lowestreception power, or a reference signal that has highest reception powerin case of presence of a plurality of the first devices. Thisconfiguration produces an effect of determining the threshold by using areference signal that has lowest reception power, or a reference signalthat has highest reception power in case of presence of a plurality ofthe first devices.

In addition, according to the first aspect, the control unit maydetermine the threshold by using at least any one of a battery residualamount of the information processing device, a volume of data handled bythe information processing device, a type of the data, and acommunication environment of the information processing device. Thisconfiguration produces an effect of determining the threshold by usingat least any one of the battery residual amount of the informationprocessing device, the volume of data handled by the informationprocessing device, the type of the data, and the communicationenvironment of the information processing device.

In addition, according to the first aspect, the control unit may updatethe threshold for every reception of the reference signal from the firstdevice. This configuration produces an effect of updating the thresholdfor every reception of the reference signal from the first device.

In addition, according to the first aspect, the control unit may updatethe threshold in case of detection of movement of the informationprocessing device or the first device. This configuration produces aneffect of updating the threshold in case of detection of movement of theinformation processing device or the first device.

In addition, according to the first aspect, the control unit may bringthe packet monitoring state into a sleep state for a period specified onthe basis of a size of the packet not addressed to the informationprocessing device in a case where reception power of the packet notaddressed to the information processing device is high with respect tothe threshold. This configuration produces an effect of bringing thepacket monitoring state into the sleep state for the period specified onthe basis of the size of the packet not addressed to the informationprocessing device in the case where reception power of the packet notaddressed to the information processing device is high with respect tothe threshold.

In addition, according to the first aspect, the control unit may bringthe packet monitoring state into the sleep state for at least a perioduntil an end of the packet not addressed to the information processingdevice. This configuration produces an effect of bringing the packetmonitoring state into the sleep state for at least the period until theend of the packet not addressed to the information processing device.

In addition, according to the first aspect, the control unit may bringthe packet monitoring state into the sleep state for a period of a sumof a period until an end of the packet not addressed to the informationprocessing device and a predetermined period. This configurationproduces an effect of bringing the packet monitoring state into thesleep state for the period of the sum of the period until the end of thepacket not addressed to the information processing device and thepredetermined period.

In addition, according to the first aspect, the predetermined period maybe a value that corresponds to any one of short inter frame space (shortIFS) (SIFS), DCF IFS (DIFS), and a transmission period of a responsesignal for the packet not addressed to the information processingdevice. This configuration produces an effect that the predeterminedperiod is any one of SIFS, DIFS, and the transmission period of theresponse signal for the packet not addressed to the informationprocessing device.

In addition, according to the first aspect, the control unit may specifythe end of the packet not addressed to the information processing deviceon the basis of length stored in a PHY header of the packet notaddressed to the information processing device. This configurationproduces an effect of specifying the end of the packet not addressed tothe information processing device on the basis of length stored in thePHY header of the packet not addressed to the information processingdevice.

In addition, according to the first aspect, the control unit may detectthe packet not addressed to the information processing device on thebasis of Basic Service Set (BSS) Color contained in a PHY header of thereceived packet. This configuration produces an effect of detecting thepacket not addressed to the information processing device on the basisof BSS Color contained in the PHY header of the received packet.

In addition, according to the first aspect, the control unit may notifya first device about the threshold, the first device transmitting apacket addressed to the information processing device. Thisconfiguration produces an effect of notifying the first device about thethreshold. The first device transmits the packet addressed to theinformation processing device.

Effects of the Invention

The present technology produces an excellent advantage of improving useefficiency of radio resources. Note that advantages to be offered arenot limited to the aforementioned advantages, but may be any ofadvantages described in the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a functional configuration example ofan information processing device 100 according to an embodiment of thepresent technology.

FIG. 2 is a diagram schematically showing a state transition example ofthe information processing device 100 according to the embodiment of thepresent technology.

FIG. 3 is a diagram showing a configuration example of a packet to betransmitted or received by the information processing device 100according to the embodiment of the present technology.

FIG. 4 is a diagram showing an example of packet communication exchangedbetween respective devices according to the embodiment of the presenttechnology.

FIG. 5 is a diagram showing an example of packet communication exchangedbetween the respective devices according to the embodiment of thepresent technology.

FIG. 6 is a flowchart showing an example of processing procedures of apacket monitoring process performed by the information processing device100 according to the embodiment of the present technology.

FIG. 7 is a diagram showing a configuration example of a sleepdetermination power threshold notification packet to be transmitted andreceived by the information processing device 100 according to theembodiment of the present technology.

FIG. 8 is a flowchart showing an example of processing procedures of asleep determination power threshold update process and a sleepdetermination power threshold notification process performed by theinformation processing device 100 according to the embodiment of thepresent technology.

FIG. 9 is a block diagram showing an example of a general configurationof a smartphone.

FIG. 10 is a block diagram showing an example of a general configurationof a car navigation device.

FIG. 11 is a block diagram showing an example of a general configurationof a wireless access point.

MODES FOR CARRYING OUT THE INVENTION

Modes for carrying out the present technology (hereinafter referred toas embodiments) are described hereinbelow. The description is presentedin the following order.

1. Embodiment (example of packet monitoring state control based onreception power of packet not addressed to own-device)

2. Application Example

1. Embodiment

[Functional Configuration Example of Information Processing Device]

FIG. 1 is a block diagram showing a functional configuration example ofan information processing device 100 according to an embodiment of thepresent technology.

The information processing device 100 includes a data processing unit110, a signal processing unit 120, a wireless interface unit 130, anantenna 140, a storage unit 150, and a control unit 160.

For example, the information processing device 100 may be constituted bya stationary or portable information processing device having a wirelesscommunication function. For example, the stationary informationprocessing device herein is an information processing device such as anaccess point of a wireless local area network (LAN) system, or a basestation. On the other hand, for example, the portable informationprocessing device is an information processing device such as asmartphone, a cellular phone, or a tablet-type terminal.

It is also assumed that the information processing device 100 has acommunication function in conformity with wireless LAN standards ofInstitute of Electrical and Electronic Engineers (IEEE) 802.11, forexample. The wireless LAN may be a network utilizing wireless fidelity(Wi-Fi), Wi-Fi Direct, or Wi-Fi CERTIFIED Miracast specification(technical specification name: Wi-Fi Display). Alternatively, theinformation processing device 100 may perform wireless communicationutilizing other communication systems.

The data processing unit 110 is configured to process various types ofdata under control by the control unit 160. For example, the dataprocessing unit 110 performs a process for adding a media access control(MAC) header, an error detection code and the like to data received froman upper layer to generate a packet for wireless transmission. The dataprocessing unit 110 subsequently supplies the generated packet to thesignal processing unit 120.

Moreover, for example, the data processing unit 110 performs headeranalysis, a packet error detection process and the like for a bit stringreceived from the signal processing unit 120 at the time of datareception, and supplies processed data to the upper layer. For example,the data processing unit 110 also notifies the control unit 160 about aheader analysis result, a packet error detection result and the like.

The signal processing unit 120 is configured to perform various types ofsignal processing under control by the control unit 160. For example,the signal processing unit 120 encodes input data received from the dataprocessing unit 110 on the basis of coding and a modulation scheme setby the control unit 160, and adds a preamble and a physical layer (PHY)header to the encoded input data at the time of transmission. The signalprocessing unit 120 subsequently supplies a transmission symbol streamobtained by the signal processing to the wireless interface unit 130.

Moreover, for example, the signal processing unit 120 detects a preambleand a PHY header from a reception symbol stream received from thewireless interface unit 130, decodes the reception symbol stream, andsupplies the decoded reception symbol stream to the data processing unit110 at the time of reception. For example, the signal processing unit120 further notifies the control unit 160 about a PHY header detectionresult and the like.

The wireless interface unit 130 is an interface connected with otherinformation processing devices via wireless communication to transmitand receive various types of information. For example, the wirelessinterface unit 130 converts input from the signal processing unit 120into analog signals, amplifies and filters the analog signals, andup-converts the analog signals to a predetermined frequency to transmitthe up-converted analog signals to the antenna 140 at the time oftransmission.

Moreover, for example, the wireless interface unit 130 performs reversedprocesses for input from the antenna 140, and supplies a processingresult to the signal processing unit 120 at the time of reception. Notethat the wireless interface unit 130 is an example of a reception unitaccording to the appended claims.

The storage unit 150 functions as a work area for data processing by thecontrol unit 160, and as a recording medium for retaining various typesof data. The storage unit 150 may be constituted by a storage mediumsuch as a non-volatile memory, a magnetic disk, an optical disk, and amagneto-optical (MO) disk, for example. Note that the non-volatilememory may be an electrically erasable programmable read-only memory(EEPROM) or an erasable programmable ROM (EPROM), for example. Inaddition, the magnetic disk may be a hard disk or a disc-shapedmagnetic-body disk, for example. In addition, the optical disk may be acompact disk (CD), a digital versatile disc recordable (DVD-R), or aBlu-Ray disc (BD (registered trademark)), for example.

The control unit 160 is configured to control a reception operation anda transmission operation of each of the data processing unit 110 and thesignal processing unit 120. For example, the control unit 160 performsinformation passing between units, communication parameter setting, andpacket scheduling of the data processing unit 110.

For example, the control unit 160 controls a packet monitoring state(e.g. state shown in FIG. 2) on the basis of reception power of a packetin case of detection of reception of a packet not addressed to theown-device (information processing device 100). In this case, thecontrol unit 160 may control the packet monitoring state on the basis ofa comparison result between the reception power of the packet notaddressed to the own-device, and a threshold (e.g. sleep determinationpower threshold shown in FIG. 6).

[State Transition Example of Information Processing Device]

FIG. 2 is a diagram schematically showing a state transition example ofthe information processing device 100 according to the embodiment of thepresent technology.

Presented in the embodiment of the present technology is an example inwhich the information processing device 100 shifts to any one of apacket transmission state (Tx state) 301, a packet reception state (Rxstate) 302, a packet detection state (listen state) 303, and a sleepstate 304.

Each of the packet transmission state 301 and the packet reception state302 is such a state that all of the data processing unit 110, the signalprocessing unit 120, the wireless interface unit 130, and the controlunit 160 operate in linkage with each other. Accordingly, a relativelylarge amount of power is consumed by the information processing device100. For example, the packet transmission state 301 is often a most highpower consumption state requiring operation of a signal amplifier (poweramplifier).

Each of the packet detection state 303 and the sleep state 304 is apacket monitoring state.

The packet detection state 303 is such a state that a preamble detectionsection in each of the wireless interface unit 130 and the signalprocessing unit 120 operates. In addition, the data processing unit 110awakens once a preamble is detected in the packet detection state 303.As a result, the packet detection state 303 shifts to the packetreception state 302. Furthermore, power consumption in the packetdetection state 303 is smaller than power consumption in each of thepacket transmission state 301 and the packet reception state 302.

The sleep state 304 is such a state that only the control unit 160operates. Accordingly, power consumption in the sleep state 304 islowest in the four states described above. In addition, transition tothe sleep state 304 is made in a case where a particular condition ismet after detection of a preamble in the packet detection state 303.FIG. 6 shows this transition example.

[Packet Configuration Example]

FIG. 3 is a diagram illustrating a configuration example of a packet tobe transmitted or received by the information processing device 100according to the embodiment of the present technology.

The packet is constituted by a PHY header 171, Parity 172, an MAC header173, DATA 174, and a cyclic redundancy check (CRC) 175.

The PHY header 171 stores basic service set (BSS) Color and Length. Notethat a network constituted by an information processing devicefunctioning as an access point (AP) (master station) is referred to asBSS in the description.

BSS Color is information introduced by IEEE802.11ah. For example, an APdeclares unique BSS Color for each BSS, describes this BSS Color in thePHY header 171 of a packet, and transmits the packet. A device havingreceived the packet is capable of determining whether or not thereceived packet is a packet for own-BSS (i.e., presence or absence of apossibility that the packet has been addressed to the own-device). Inthis case, the presence or absence of the possibility that the packethas been addressed to the own-device is determined on the basis of anintroduction part of the packet. Accordingly, in case of reception of apacket addressed to a different device (packet not addressed toown-device), processes after the reception are omitted to reduce powerconsumption for reception.

Length is information for specifying a length of a packet.

The MAC header 173 stores a destination address (Rx Address). The MACheader 173 may further store CRC. In case of the MAC header 173 storingCRC, the destination is determinable with reference to a head part ofthe packet.

For example, suppose that an error detection method using the CRC 175 isadopted to detect whether or not received packet data contains an error.According to this method, a received packet is discarded in case ofdetection of an error in the packet, for example. On the other hand, incase of detection of no error in a received packet, the MAC header 173is read to determine whether or not the packet has been addressed to theown-device. In a case where it is determined that the packet has notbeen addressed to the own-device, the received packet is discardedregardless of correctness of contents of the packet.

According to this error detection method, not only the MAC header butalso the entire packet up to the final part need to be demodulated. Inthis case, the presence or absence of an error in data is determinedafter reception of the final part of the packet. Accordingly,determination is made only after reception of the entire packet even incase of the packet containing an error in the MAC header, and the packetcontaining no error in the MAC header but not addressed to theown-device, for example.

On the other hand, according to a method using BSS Color stored in thePHY header 171, a received packet not addressed to the own-device isdeterminable with reference to a head part of the packet. In addition,according to a method using CRC stored in the MAC header 173, a receivedpacket not addressed to the own-device is determinable with reference toa part of the MAC header 173. According to these methods, a process forreceiving a remaining part of a packet not addressed to the own-deviceneed not be performed.

As described above, a packet not addressed to the own-device isdeterminable before reception of the entire packet. For example, supposethat a process for receiving a remaining part of a packet is notperformed in accordance with determination based on BSS Color that thepacket has not been addressed to the own-device. In this case, it isimportant to improve use efficiency of radio resources by increasingreception opportunities in a period for receiving the remaining part ofthe packet. For example, suppose that reception power of a packet notaddressed to the own-device is sufficiently low, and that receptionpower of a desired packet (packet addressed to own-device) issufficiently high. In this case, the information processing device 100may shift to the packet detection state (listen state) 303 (shown inFIG. 2) in the period of the packet not addressed to the own-device toincrease reception opportunities. As a result of this shift, systemthroughput is expected to improve.

Accordingly, presented in the embodiment of the present technology is anexample which increases reception opportunities in a period of a packetnot addressed to the own-device to improve system throughput.

[Packet Communication Example]

FIGS. 4 and 5 illustrate a packet communication example betweenrespective devices according to the embodiment of the presenttechnology.

A simplified configuration example constituted by the informationprocessing device 100, an information processing device 201, aninformation processing device 202, and an information processing device203 is shown in each of a of FIG. 4 and a of FIG. 5.

A flow of packets exchanged between the information processing device100, the information processing device 201, the information processingdevice 202, and the information processing device 203 is schematicallyshown in each of b of FIG. 4 and b of FIG. 5.

Rectangles 310, 315, 320, and 323 schematically indicate transmittedpackets, while rectangles 313, 314, 322, 333, 334, and 342 schematicallyindicate received packets (or packets to be received later) in b of FIG.4 and b of FIG. 5. Moreover, arrows 311, 312, 321, 331, 332, and 341schematically indicate flows of transmitted packets. Note that a part ofrectangles and arrows indicating acknowledgment (ACK) is not shown.

In addition, each horizontal axis in each of b of FIG. 4 and b of FIG. 5represents a time axis. Each height (length in vertical direction) ofthe rectangles indicating packets at a receiving device representsreception power of the corresponding received packet (reception signalintensity).

In addition, according to the example illustrated in FIG. 4, theinformation processing device 100 and the information processing device201 are located relatively close to each other, while the informationprocessing device 100 and the information processing device 202 arelocated relatively far from each other. On the other hand, according tothe example illustrated in FIG. 5, the information processing device 100and the information processing device 201 are located relatively farfrom each other, while the information processing device 100 and theinformation processing device 202 are located relatively close to eachother.

In addition, according to the examples illustrated in FIGS. 4 and 5,each of the information processing device 202 and the informationprocessing device 203 indicated by a triangle functions as an AP (masterstation), while each of the information processing device 100 and theinformation processing device 201 indicated by a rectangle functions asa subsidiary device (slave station) of the corresponding AP. Morespecifically, it is assumed that the information processing device 100functions as a subsidiary device (slave station) of the informationprocessing device 202, and that the information processing device 201functions as a subsidiary device (slave station) of the informationprocessing device 203. Accordingly, FIGS. 4 and 5 illustrate examples ofa communication system constituted by combinations of one access pointand one subsidiary device.

Note that target system configurations according to the embodiment ofthe present technology are not limited to these specific examples. Forexample, while each of FIGS. 4 and 5 illustrates an example of acommunication system constituted by combinations of one access point andone subsidiary device, the number of access points and subsidiarydevices are not limited to these values. For example, the embodiment ofthe present technology is applicable to a communication systemconstituted by combinations of one access point and a plurality ofsubsidiary devices.

Alternatively, for example, the embodiment of the present technology isalso applicable to a network where a plurality of devices are mutuallyconnected to each other via one-to-one wireless communication betweenthe plurality of devices (e.g. mesh network and ad hoc network).

FIG. 4 illustrates an example in which packets addressed to theown-device (desired packets) is difficult to receive by the informationprocessing device 100.

For example, suppose that the information processing device 202transmits data 320 to the information processing device 100 (321) aftertransmission of data 310 from the information processing device 201 tothe information processing device 203 (311). Further assumed in thedescription is that the data 310 is referred to as a packet addressed toa different device (packet not addressed to own-device), and that thedata 320 is a desired packet (packet addressed to own-device) on thebasis of the information processing device 100.

In this case, the information processing device 100 also receives thedata 310 from the information processing device 201 located relativelyclose to the information processing device 100 (312, 314). The data 310is a packet addressed to a different device different from theinformation processing device 100, and therefore becomes an interferingwave for the information processing device 100. In addition, receptionpower of the data 310 is high (314) in the state that the informationprocessing device 201 and the information processing device 100 arelocated relatively close to each other.

On the other hand, reception power of the data 320 is low (322) in caseof transmission of the data 320 to the information processing device 100from the information processing device 202 located relatively far fromthe information processing device 100 (321). In this case, decoding ofthe desired packet (packet 322) may be difficult even if reception ofthe desired packet is attempted by the information processing device100. In this case, transmission of the ACK 323 from the informationprocessing device 100 becomes difficult.

In case of high reception power of a packet addressed to the differentdevice corresponding to an interfering wave (data 314) and low receptionpower of a desired packet (data 322) as in this example, decoding of adesired packet may be difficult even if reception of the desired packetis attempted. In this case, transition to the sleep state 304 (shown inFIG. 2) contributes to reduction of the power consumption of theinformation processing device 100 which has received the packetaddressed to the different device and having high reception power.

FIG. 5 illustrates an example of success achieved by the informationprocessing device 100 in receiving a packet addressed to the own-device(desired packet).

For example, suppose that the information processing device 202transmits data 340 to the information processing device 100 (341) aftertransmission of data 330 from the information processing device 201 tothe information processing device 203 (331). Further assumed in thedescription is that the data 330 is referred to as a packet addressed toa different device (packet not addressed to own-device), and that thedata 340 is a desired packet (packet addressed to own-device) on thebasis of the information processing device 100.

In this case, the information processing device 100 also receives thedata 330 from the information processing device 201 (332, 334). However,reception power of the data 330 is low in the state that the informationprocessing device 100 and the information processing device 201 arelocated relatively far from each other (334).

In addition, in case of transmission of the data 340 from theinformation processing device 202 to the information processing device100 (341), reception power of the data 340 is high in the state that theinformation processing device 100 and the information processing device202 are located relatively close to each other (342). In this case, adesired packet (packet 342) may be decodable at the time of reception ofthe desired packet attempted by the information processing device 100.In this case, the information processing device 100 is capable oftransmitting the ACK 343.

As described above, decoding of the desired packet (data 342) may beallowed even during transmission of the packet (data 334) addressed tothe different device and corresponding to an interfering wave on theassumption that sufficiently low reception power of the packet addressedto the different device and sufficiently high reception power of thedesired packet (data 342) are expected. In this case, it is consideredthat transition to the packet detection state (listen state) 303 (shownin FIG. 2) contributes to improvement of system throughput of theinformation processing device 100 which has received the packetaddressed to the different device and having low reception power.

It is therefore important to appropriately select the state of theinformation processing device 100 on the basis of a relationship betweenreception power of a packet addressed to a different device andcorresponding to an interfering wave (data 314, 334), and receptionpower of a desired packet (data 322, 342). Accordingly, describedhereinafter is an example of selection of the state of the informationprocessing device 100 on the basis of the relationship between receptionpower of a packet addressed to a different device and corresponding toan interfering wave, and reception power of a desired packet.

[Operation Example of Information Processing Device]

FIG. 6 is a flowchart showing an example of processing procedures of apacket monitoring process performed by the information processing device100 according to the embodiment of the present technology. FIG. 6 showsan example that an initial state of the information processing device100 is the packet detection state 303 shown in FIG. 2.

Initially, the control unit 160 of the information processing device 100acquires predicted reception power of a desired packet (packet addressedto own-device) (step S801).

For example, in case of the information processing device 100constituting a slave station, the control unit 160 is capable ofacquiring predicted reception power of a desired packet transmitted froma master station connected to the information processing device 100 onthe basis of a reference signal (such as beacon) transmitted from themaster station. For example, reception power of a beacon (latest beacon)received immediately before (or value calculated on the basis of beacon)may be designated as predicted reception power. In addition, forexample, average reception power of beacons in a certain period (orvalue calculated on the basis of average) may be designated as predictedreception power of a desired packet. In this case, an average may becalculated with lowered degrees of importance of old beacons, and raiseddegrees of importance of new beacons.

On the other hand, in case of the information processing device 100constituting a master station, for example, the control unit 160 iscapable of calculating predicted reception power of a desired packetreceived from one of a plurality of slave stations connected to theown-device on the basis of a reference signal transmitted from thecorresponding slave station. In this case, for example, the referencesignal may be a certain data signal transmitted from each of the slavestations. For example, average reception power of reference signals ofthe respective slave stations (latest reference signals) receivedimmediately before for each slave station (or value calculated on thebasis of average) may be designated as predicted reception power of adesired packet. Alternatively, for example, average reception power ofreference signals of the respective slave stations received in a certainperiod for each slave station (or value calculated on the basis ofaverage) may be designated as predicted reception power of a desiredpacket. In these cases, for example, reference signals from all slavestations may be handled equally, or degrees of importance of referencesignals may be varied for each slave station to calculate predictedreception power of a desired packet. For example, the degrees ofimportance may be determined in accordance with transmission frequenciesof respective slave stations. For example, the degrees of importance ofreception power of slave stations more frequently transmitting packetsmay be raised, while the degrees of importance of reception power ofslave stations less frequently transmitting packets may be lowered.

In addition, in case of a reference signal including description of anactual transmission power level, for example, predicted reception powerof a desired packet may be acquired on the basis of the transmissionpower level described in the reference signal.

A device which performs transmission power control herein may switchtransmission power for each transmission destination during packettransmission. For example, a master station may switch transmissionpower for each slave station during packet transmission, rather thanequalize packet transmission for each slave station. Moreover, a masterstation may increase transmission power to allow respective slavestations to receive beacons during transmission. In this case, atransmission device may store actual transmission power in a packet tobe transmitted at the time of transmission to notify a transmissiondestination of the packet about the actual transmission power.Accordingly, a reception device receiving the packet is capable ofrecognizing a range supported by the transmission device.

Thereafter, the control unit 160 determines a sleep determination powerthreshold on the basis of the predicted reception power of the desiredpacket (step S802). For example, the sleep determination power thresholdis determination information used for determining whether to transit tothe sleep state 304 shown in FIG. 2 at the time of detection of a packetaddressed to a different device.

For example, the control unit 160 may calculate the sleep determinationpower threshold on the basis of the predicted reception power of thedesired packet, and on reception performance of the informationprocessing device 100 (e.g. resistance to interfering wave). Forexample, predetermined calculation may be performed for the predictedreception power of the desired packet and the reception performance ofthe information processing device 100 to calculate the sleepdetermination power threshold.

The reception performance herein is a characteristic peculiar to thedevice. For example, the reception performance collectively refers to ananalog characteristic (e.g. noise figure) variable in accordance withperformance of an antenna and an amplifier, and performance in digitalprocessing (e.g. channel estimation).

In case of the information processing device 100 constituting a slavestation, for example, reception power of a desired packet received froma master station connected to the information processing device 100 isexpected to be high in a state that reception power of a beacon from themaster station is high. In this case, it is highly probable that thedesired packet is decodable even under a relatively high-levelinterfering wave. Accordingly, the sleep determination power thresholdmay be set to a high value in case of high reception power of a beaconfrom the master station.

In addition, in case of the information processing device 100constituting a slave station, for example, reception power of a desiredpacket received from a master station connected to the informationprocessing device 100 is expected to be low in a state that receptionpower of a beacon from the master station is low. In this case, it ishighly probable that the desired packet is not decodable under arelatively high-level interfering wave. Accordingly, transition to thesleep state 304 (shown in FIG. 2) is preferable even under a low-levelinterfering wave in case of low reception power of a beacon from themaster station. Accordingly, the sleep determination power threshold maybe set to a low value in case of low reception power of a beacon fromthe master station.

On the other hand, in case of the information processing device 100constituting a master station, for example, the sleep determinationpower threshold may be set on the basis of a slave station indicatinglowest reception power to allow easy transmission to the sleep state 304(shown in FIG. 2). In addition, in case of the information processingdevice 100 constituting a master station, for example, the sleepdetermination power threshold may be set on the basis of a slave stationindicating highest reception power to allow easy transition to thepacket detection state (listen state) 303 (shown in FIG. 2). In thiscase, system throughput is adjustable to higher throughput.

Alternatively, the sleep determination power threshold may be set on thebasis of other determination references. For example, in case of theinformation processing device 100 constituted by a portable device (e.g.mobile device), the sleep determination power threshold may be adjustedon the basis of a battery residual amount of the information processingdevice 100. In a case where the battery residual amount of theinformation processing device 100 is small with respect to a threshold,the sleep determination power threshold may be lowered to allow easytransition to the sleep state 304 (shown in FIG. 2).

Alternatively, for example, the sleep determination power threshold maybe adjusted on the basis of data handled by the information processingdevice 100 (e.g., data volume and traffic status). In case of a largevolume of data relayed by the information processing device 100functioning as a relay, for example, it is considered that transition tothe sleep state 304 (shown in FIG. 2) is not preferable. Accordingly, incase of a large volume of data handled by the information processingdevice 100, the sleep determination power threshold is raised to preventeasy transition to the sleep state 304 (shown in FIG. 2).

Alternatively, for example, the sleep determination power threshold maybe adjusted on the basis of a communication environment of theinformation processing device 100 (e.g. reception frequency, congestionlevel, number of connected devices, and number of adjacent BSS), typesof data handled by the information processing device 100 (e.g. degree ofpriority and degree of importance), and others. In addition, forexample, the sleep determination power threshold may be determined onthe basis of a combination of two or more of the plurality ofdetermination references described above.

As described above, the control unit 160 may determine the sleepdetermination power threshold on the basis of reception power of areference signal from a first device which transmits a packet addressedto the own-device (e.g. communication partner of information processingdevice 100). In this case, for example, the control unit 160 maydetermine the sleep determination power threshold on the basis of thelatest reference signal in the reference signals received from the firstdevice, or a plurality of the reference signals received from the firstdevice. In addition, in case of presence of a plurality of the firstdevices, for example, the control unit 160 may determine the sleepdetermination power threshold on the basis of the reference signalindicating the lowest reception power, or the reference signalindicating the highest reception power. Furthermore, for example, thecontrol unit 160 may determine the sleep determination power thresholdon the basis of at least any one of a battery residual amount of theinformation processing device 100, a data volume of data handled by theinformation processing device 100, a type of the data, and acommunication environment of the information processing device 100.

Thereafter, the control unit 160 determines whether or not a packet hasbeen received (step S803). In case of determination that no packet hasbeen received (step S803), monitoring continues.

In case of determination that a packet has been received (step S803),the control unit 160 acquires BSS Color stored in the PHY header 171(shown in FIG. 3) of the received packet. The control unit 160subsequently determines whether or not an acquired value of BSS Coloragrees with a value of BSS Color of BSS to which the own-device belongs(step S804). Note that the information processing device 100 retains thevalue of BSS Color of BSS to which the own-device belongs beforehandwith reference to notification from a master station of BSS to which theown-device belongs. Note that step S804 is an example of a detectionprocedure according to the appended claims.

In case of agreement between both the values of BSS Color (step S804),it is considered that the packet is a packet addressed to BSS to whichthe information processing device 100 belongs. In this case, there is apossibility that the packet has been addressed to the own-device.Accordingly, the control unit 160 shifts to the packet reception state302 shown in FIG. 2 to perform a packet reception/decipherment process(step S805). As a result, whether or not the packet has been addressedto the own-device is determinable.

Note that, while FIG. 6 shows an example of determination that thereceived packet is not a packet addressed to the own-device by using BSSColor stored in the PHY header 171, this determination may be made byusing other information. For example, in case of the MAC header 173storing CRC, the determination that the received packet is not a packetaddressed to the own-vehicle may be made on the basis of a head part ofthe packet by using CRC. In these cases, a process for receiving aremaining part of the packet need not be performed.

In case of disagreement between both the values of BSS Color (stepS804), the packet is not a packet addressed to BSS to which theinformation processing device 100 belongs. In this case, there is nopossibility that the packet is a packet addressed to the own-device.Accordingly, the control unit 160 determines whether or not receptionpower of the received packet exceeds the sleep determination powerthreshold (step S806).

In case of excess of the reception power of the packet over the sleepdetermination power threshold (step S806), the control unit 160 shiftsto the sleep state 304 shown in FIG. 2 to perform a sleep process untilan end of the received packet (step S807). In other words, the stateshifts to the sleep state 304 shown in FIG. 2 to come into a sleepperiod until the end of the received packet. This sleep period is asleep period provided for each packet, and recognized as a micro sleep,for example.

Note that a packet length is acquired with reference to Length stored inthe PHY header 171 shown in FIG. 3.

In addition, while the example of the sleep period presented herein isan example period continuing until an end of a received packet (periodbased on length of received packet), other periods may be defined as thesleep period. For example, the sleep period may be a sum of a perioduntil an end of a received packet and a period of short inter framespace (short IFS) (SIFS). Alternatively, for example, the sleep periodmay be a sum of a period until an end of the received packet and aperiod of DCF IFS (DIFS).

In addition, for example, a time until ACK transmission may berecognizable without a need of deciphering text of the received packet.In this case, the sleep period may be a period until ACK transmission.

In case of no excess of the reception power of the packet over the sleepdetermination power threshold (step S806), the control unit 160 shiftsto the packet detection state 303 shown in FIG. 2 to monitor receptionof a packet (step S808). Note that steps S806 through S808 correspond toan example of a control procedure according to the appended claims.

As described above, the control unit 160 is capable of detectingreception of a packet not addressed to the own-device on the basis ofBSS Color stored in the PHY header 171 (shown in FIG. 3) of the receivedpacket. Then, in case of detection of reception of a packet notaddressed to the own-device, the control unit 160 controls a packetmonitoring state on the basis of the reception power of the packet. Inthis case, the control unit 160 controls the packet monitoring state onthe basis of a comparison result between the reception power of packetnot addressed to the own-device and the sleep determination powerthreshold.

In addition, in case of excess of the reception power of the packet notaddressed to the own-device over the sleep determination powerthreshold, the control unit 160 shifts the packet monitoring state tothe sleep state 304 (shown in FIG. 2) for a period specified inaccordance with a size of the packet to come into a sleep state. Forexample, the period specified in accordance with the size of the packetnot addressed to the own-device herein may be a sum of a period until anend of the packet not addressed to the own-device, and a predeterminedperiod. For example, the predetermined period may be any one of SIFS,DIFS, and a transmission period of a response signal for the packet notaddressed to the own-device (e.g. transmission period of ACK).

In addition, the control unit 160 may specify an end of a packet notaddressed to the own-device with reference to Length stored in the PHYheader 171 (shown in FIG. 3) of the packet.

In addition, the control unit 160 may control a packet detection stateon the basis of a result of comparison between reception power of apacket addressed to a different device and predicted reception power ofa desired packet (e.g. ratio of one reception power to the otherreception power) at the detection timing of the packet addressed to thedifferent device in wireless packet communication. For example, in acase where the “(predicted reception power of desired packet)/(receptionpower of packet addressed to different device)” is a sufficiently largevalue, the packet detection state (listen state) 303 shown in FIG. 2 maybe set to increase reception opportunities. On the other hand, in a casewhere the “(predicted reception power of desired packet)/(receptionpower of packet addressed to different device)” is a small value, forexample, the sleep state 304 shown in FIG. 2 may be set to reduce powerconsumption.

Note that the example herein is an example of acquiring predictedreception power of a desired packet and a sleep determination powerthreshold for every reception of a packet. However, predicted receptionpower of a desired packet and a sleep determination power threshold maybe acquired at different timing. For example, predicted reception powerof a desired packet and a sleep determination power threshold may beacquired at the time of reception of a packet addressed to theown-device. FIG. 8 shows this example.

Alternatively, in case of the information processing device 100constituting a slave station, for example, predicted reception power ofa desired packet and a sleep determination power threshold may beacquired at the time of reception of a beacon from a master station.Alternatively, for example, predicted reception power of a desiredpacket and a sleep determination power threshold may be acquired afteran elapse of a predetermined period, or at the time of reception of apredetermined number of packets.

Alternatively, in case of the information processing device 100constituted by a cellular phone, for example, predicted reception powerof a desired packet and a sleep determination power threshold may beacquired at the time of detection of movement of the informationprocessing device 100. Note that the movement of the informationprocessing device 100 (movement of position of information processingdevice 100) is detectable on the basis of a sensor for detecting acondition of the information processing device 100 (e.g. built-in sensorof information processing device 100). For example, this sensor may beconstituted by a gyro sensor, an acceleration sensor, a globalpositioning system (GPS) sensor, or other sensors. Alternatively, forexample, predicted reception power of a desired packet and a sleepdetermination power threshold may be acquired at the time of detectionof movement of a communication partner device of the informationprocessing device 100. In this case, the movement of the communicationpartner device is detectable by the information processing device 100with reference to notification from the communication partner device(e.g. exchange of signal including information indicating movement).

Alternatively, in case of the information processing device 100constituting a slave station, and constituted by a portable device, forexample, predicted reception power of a desired packet and a sleepdetermination power threshold may be acquired at the time of a distancechange between the information processing device 100 and a masterstation. This distance change is detectable on the basis of a change ofreception power of a beacon from a master station, or sensor informationreceived from the respective sensors described above, for example.

As described above, the control unit 160 may update a sleepdetermination power threshold in case of detection of movement of theinformation processing device 100 or the first device (e.g.communication partner of information processing device 100).Alternatively, the control unit 160 may update the sleep determinationpower threshold in case of a change of a relative positionalrelationship between the information processing device 100 and the firstdevice.

In addition, predicted reception power of a desired packet and a sleepdetermination power threshold may be acquired at times different fromeach other, for example.

[Communication Example of Sleep Determination Power ThresholdNotification Packet]

FIG. 7 is a diagram illustrating a configuration example of a sleepdetermination power threshold notification packet to be transmitted andreceived by the information processing device 100 according to theembodiment of the present technology.

The sleep determination power threshold notification packet isconstituted by a PHY header 181, a MAC header 182, DATA 183, and CRC184. FIG. 7 shows an example of the DATA 183 storing a sleepdetermination power threshold.

As described above, the control unit 160 of the information processingdevice 100 transmits a determined sleep determination power thresholdcontained in a sleep determination power threshold notification packetto notify a communication partner about the sleep determination powerthreshold set for the own-device. A device having received the sleepdetermination power threshold notification packet is capable oftransmitting a packet with reference to the sleep determination powerthreshold contained in the sleep determination power thresholdnotification packet in case of transmission of the packet to theinformation processing device 100. For example, the device havingreceived the sleep determination power threshold notification packet iscapable of controlling transmission power level for packet transmissionto the information processing device 100 on the basis of the sleepdetermination power threshold contained in the sleep determination powerthreshold notification packet.

[Operation Example of Information Processing Device]

FIG. 8 is a flowchart showing an example of processing procedures of asleep determination power threshold update process and a sleepdetermination power threshold notification process performed by theinformation processing device 100 according to the embodiment of thepresent technology.

FIG. 8 shows an example of updating a sleep determination powerthreshold by the information processing device 100 for every receptionof a packet addressed to the own-device. Updating is performed by usingreception power of the packet addressed to the own-device with referenceto the received packet as a reference signal. By updating the sleepdetermination power threshold for every reception of a packet addressedto the own-device as described above, accurate estimation of receptionpower of a desired packet is realizable in a manner followingfluctuations of an environment for the information processing device100.

FIG. 8 also shows an example of notifying a communication partner aboutthe updated sleep determination power threshold at intervals of apredetermined period. By this method, the communication partner isnotified about the latest sleep determination power threshold atappropriate timing.

Initially, the control unit 160 of the information processing device 100determines whether or not a packet addressed to the own-device has beenreceived (step S811). In case of determination that no packet addressedto the own-device has been received (step S811), the flow proceeds tostep S813.

In case of determination that a packet addressed to the own-device hasbeen received (step S811), the control unit 160 updates a sleepdetermination power threshold (step S812). More specifically, thecontrol unit 160 acquires predicted reception power of a desired packet,and determines a sleep determination power threshold on the basis of thepredicted reception power of the desired packet.

Subsequently, the control unit 160 determines whether or not the currenttime is a notification time about the sleep determination powerthreshold (step S813). This notification time may be set by a useroperation, or may be automatically set by an external device, forexample.

Alternatively, the notification time may be automatically set inaccordance with an environment for the information processing device100, or other conditions. In case of determination that the current timeis not the notification time of the sleep determination power threshold(step S813), operations of the sleep determination power thresholdupdate process and the sleep determination power threshold notificationprocess end.

In case of determination that the current time is the notification timeof the sleep determination power threshold (step S813), the control unit160 transmits a sleep determination power threshold notification packetcontaining a latest sleep determination power threshold (step S813).

As described above, the control unit 160 is capable of updating thesleep determination power threshold for every reception of a referencesignal from the first device (communication partner of informationprocessing device 100).

Note that FIG. 8 shows an example of transmitting the sleepdetermination power threshold notification packet at intervals of apredetermined period. However, the sleep determination power thresholdnotification packet may be transmitted at different timing. For example,the sleep determination power threshold notification packet may betransmitted at the time of update of the sleep determination powerthreshold. Alternatively, in case of the information processing device100 constituting a master station, for example, the sleep determinationpower threshold notification packet may be transmitted at the time oftransmission of a beacon. In this case, the beacon to be transmitted maybe transmitted as the sleep determination power threshold notificationpacket.

Accordingly, reduction of power consumption during standby of a device,and maximization of system throughput are both realizable in wirelesspacket communication according to the embodiment of the presenttechnology. More specifically, the state is appropriately switchablebetween the packet detection state (listen state) 303 and the sleepstate 304 shown in FIG. 2 on the basis of reception power of a packetaddressed to a different device (packet not addressed to own-device).

Furthermore, the information processing device 100 according to theembodiment of the present technology is applicable to devices in variousfields. For example, the information processing device 100 is applicableto wireless devices provided inside an automobile (e.g. car navigationsystem and smartphone). Moreover, for example, the informationprocessing device 100 is applicable to learning aid devices used ineducational fields (e.g. tablet-type terminal). Furthermore, forexample, the information processing device 100 is applicable to wirelessdevices used in agricultural fields (e.g. terminal of cow managementsystem). Similarly, for example, the information processing device 100is applicable to respective wireless devices used in sporting fields,medical fields and others.

2. Application Example

The technology according to the present disclosure is applicable tovarious types of products. For example, the information processingdevice 100 may be practiced in the form of a smartphone, a tablet-typepersonal computer (PC), a laptop, a mobile terminal such as a portablegame console and a digital camera, a television receiver, a printer, astationary terminal such as a digital scanner and a network storage, oran in-vehicle terminal such as a car navigation device. Alternatively,the information processing device 100 may be practiced in the form of asmart meter, a vending machine, a remote monitoring device, or aterminal performing machine to machine (M2M) communication (alsoreferred to as machine type communication (MTC) terminal) such as apoint of sale (POS) terminal. Alternatively, the information processingdevice 100 may be a wireless communication module mounted on theseterminals (e.g. integrated circuit module constituted by one die).

On the other hand, the information processing device 100 may bepracticed in the form of a wireless LAN access point (also referred toas wireless base station) which has or does not have a router function.Alternatively, the information processing device 100 may be practiced inthe form of a mobile wireless LAN router. Alternatively, the informationprocessing device 100 may be a wireless communication module mounted onthese devices (e.g. integrated circuit module constituted by one die).

[2-1. First Application Example]

FIG. 9 is a block diagram showing an example of a general configurationof a smartphone 900 to which the technology according to the presentdisclosure is applicable. The smartphone 900 includes a processor 901, amemory 902, a storage 903, an external connection interface 904, acamera 906, a sensor 907, a microphone 908, an input device 909, adisplay device 910, a speaker 911, a wireless communication interface913, an antenna switch 914, an antenna 915, a bus 917, a battery 918,and an auxiliary controller 919.

For example, the processor 901 may be constituted by a centralprocessing unit (CPU) or a system on chip (SoC), and controls functionsof application layers or other layers of the smartphone 900. The memory902 includes a random access memory (RAM) and a read only memory (ROM),and stores programs executed by the processor 901 and data. The storage903 may include a storage medium such as a semiconductor memory and ahard disk. The external connection interface 904 is an interface forconnecting an external device such as a memory card or a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an imaging device such as a charge coupleddevice (CCD) and a complementary metal oxide semiconductor (CMOS), andforms a captured image. The sensor 907 may include a sensor group suchas a positioning sensor, a gyro sensor, a geomagnetic sensor, and anacceleration sensor. The microphone 908 converts voices input to thesmartphone 900 into audio signals. The input device 909 includes a touchsensor for detecting a touch to a screen of the display device 910, akeypad, a keyboard, buttons, and switches, for example, and receivesoperations or information input from a user. The display device 910includes a screen such as a liquid crystal display (LCD) and an organiclight emitting diode (OLED) display, and displays an output image fromthe smartphone 900. The speaker 911 converts audio signals input fromthe smartphone 900 into voices.

The wireless communication interface 913 supports one or more ofwireless LAN standards such as IEEE 802.11a, 11b, 11g, 11n, 11ac, and11ad, and executes wireless communication. The wireless communicationinterface 913 may communicate with other devices via wireless LAN accesspoints in an infrastructure mode. In addition, the wirelesscommunication interface 913 may directly communicate with other devicesin a direct communication mode such as ad hoc mode and Wi-Fi Direct.Note that one of two terminals operates as an access point in Wi-FiDirect unlike the ad hoc mode. However, communication is directlyexecuted between these terminals. Typically, the wireless communicationinterface 913 may include a baseband processor, a radio frequency (RF)circuit, a power amplifier and the like. The wireless communicationinterface 913 may be a one-chip module which integrates a memory storinga communication control program, a processor executing this program, andassociated circuits. The wireless communication interface 913 maysupport other types of wireless communication system such as ashort-range wireless communication system, a close wirelesscommunication system, and a cellular communication system, as well asthe wireless LAN system. Then antenna switch 914 switches connection ofthe antenna 915 between a plurality of circuits included in the wirelesscommunication interface 913 (such as circuits for different wirelesscommunication systems). The antenna 915 includes a single or a pluralityof antenna elements (such as a plurality of antenna elementsconstituting MIMO antenna) used for wireless signal transmission andreception via the wireless communication interface 913.

Note that the configuration of the smartphone 900 is not limited to theexample shown in FIG. 9, but may include a plurality of antennas (e.g.antennas for wireless LAN and antennas for near wireless communicationsystem). In this case, the antenna switch 914 may be eliminated from theconfiguration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 913, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to therespective blocks of the smartphone 900 shown in FIG. 9 via power supplylines partially indicated by broken lines in the figure. The auxiliarycontroller 919 secures operations associated with minimum necessaryfunctions of the smartphone 900 in a sleep mode, for example.

The control unit 160 described with reference to FIG. 1 may be mountedon the wireless communication interface 913 in the smartphone 900 shownin FIG. 9. In addition, at least a part of the functions of thesmartphone 900 may be incorporated in the processor 901 or the auxiliarycontroller 919. For example, power consumption of the battery 918decreases under the packet monitoring control described above.

Note that the smartphone 900 may operate as a wireless access point(software AP) by an application-level access point function executed bythe processor 901. Alternatively, the wireless access point function maybe performed by the wireless communication interface 913.

[2-2. Second Application Example]

FIG. 10 is a block diagram showing an example of a general configurationof a car navigation device 920 to which the technology according to thepresent disclosure is applicable. The car navigation device 920 includesa processor 921, a memory 922, a global positioning system (GPS) module924, a sensor 925, a data interface 926, a content player 927, a storagemedium interface 928, an input device 929, a display device 930, aspeaker 931, a wireless communication interface 933, an antenna switch934, an antenna 935, and a battery 938.

The processor 921 may be constituted by a CPU or an SoC, and controls anavigation function and other functions of the car navigation device920. The memory 922 includes a RAM and a ROM, and stores programsexecuted by the processor 921 and data.

The GPS module 924 measures a position of the car navigation device 920(such as latitude, longitude, and altitude) on the basis of GPS signalsreceived from a GPS satellite. For example, the sensor 925 may include asensor group such as a gyro sensor, a geomagnetic sensor, and a pressuresensor. The data interface 926 is connected to an in-vehicle network 941via a not-shown terminal to obtain data generated by a vehicle such asvehicle speed data.

The content player 927 reproduces content stored in a storage medium(such as CD and DVD) inserted into the storage medium interface 928. Forexample, the input device 929 includes a touch sensor for detecting atouch to a screen of the display device 930, buttons, switches and thelike, and receives operations or information input from a user. Thedisplay device 930 includes a screen such as an LCD display and an OLEDdisplay, and displays navigation functions or images of content to bereproduced. The speaker 931 outputs navigation functions or voices ofcontent to be reproduced.

The wireless communication interface 933 supports one or more ofwireless LAN standards such as IEEE 802.11a, 11b, 11g, 11n, 11ac, and11ad, and executes wireless communication. The wireless communicationinterface 933 may communicate with other devices via wireless LAN accesspoints in an infrastructure mode. In addition, the wirelesscommunication interface 933 may directly communicate with other devicesin a direct communication mode such as ad hoc mode and Wi-Fi Direct.Typically, the wireless communication interface 933 may include abaseband processor, an RF circuit, a power amplifier and the like. Thewireless communication interface 933 may be a one-chip module whichintegrates a memory storing a communication control program, a processorexecuting this program, and associated circuits. The wirelesscommunication interface 933 may support other types of wirelesscommunication system such as a short-range wireless communicationsystem, a close wireless communication system, and a cellularcommunication system, as well as the wireless LAN system. The antennaswitch 934 switches connection of the antenna 935 between a plurality ofcircuits included in the wireless communication interface 933. Theantenna 935 includes a single or a plurality of antenna elements usedfor wireless signal transmission and reception via the wirelesscommunication interface 933.

Note that, the configuration of the car navigation device 920 is notlimited to the example shown in FIG. 10, but may include a plurality ofantennas. In this case, the antenna switch 934 may be eliminated fromthe configuration of the car navigation device 920.

The battery 938 supplies power to the respective blocks of the carnavigation device 920 shown in FIG. 10 via power supply lines partiallyindicated by broken lines in the figure. In addition, the battery 938accumulates power supplied from the vehicle.

The control unit 160 described with reference to FIG. 1 may be mountedon the wireless communication interface 933 in the car navigation device920 shown in FIG. 10. In addition, at least a part of the functions ofthe car navigation device 920 may be incorporated in the processor 921.

In addition, the wireless communication interface 933 may function asthe information processing device 100 described above to providewireless connection to a terminal carried by a user on the vehicle.

Furthermore, the technology according to the present disclosure may berealized as an in-vehicle system (or vehicle) 940 which includes one ormore blocks of the car navigation device 920 described above, anin-vehicle network 941, and a vehicle module 942. The vehicle module 942generates vehicle data such as a vehicle speed, an engine speed, and malfunction information, and outputs the generated data to the in-vehiclenetwork 941.

[2-3. Third Application Example]

FIG. 11 is a block diagram showing an example of a general configurationof a wireless access point 950 to which the technology according to thepresent disclosure is applicable. The wireless access point 950 includesa controller 951, a memory 952, an input device 954, a display device955, a network interface 957, a wireless communication interface 963, anantenna switch 964, and an antenna 965.

The controller 951 may be constituted by a CPU or a digital signalprocessor (DSP), for example, and performs various functions of layershigher than an Internet protocol (IP) of the wireless access point 950(such as access limitation, routing, encryption, fire wall, and logmanagement). The memory 952 includes a RAM and a ROM, and storesprograms executed by the controller 951, and various types of controldata (such as terminal list, routing table, encryption key, securitysetting, and log).

The input device 954 includes buttons, switches or the like, andreceives an operation from a user. The display device 955 includes anLED lamp or the like, and displays an operation status of the wirelessaccess point 950.

The network interface 957 is a wired communication interface providingconnection between the wireless access point 950 and a wiredcommunication network 958. The network interface 957 may include aplurality of connection terminals. The wired communication network 958may be a LAN such as Ethernet (registered trademark), or may be a widearea network (WAN).

The wireless communication interface 963 supports one or more ofwireless LAN standards such as IEEE 802.11a, 11b, 11g, 11n, 11ac, and11ad, and provides wireless connection as an access point to a nearterminal. Typically, the wireless communication interface 963 mayinclude a baseband processor, an RF circuit, a power amplifier and thelike. The wireless communication interface 963 may be a one-chip modulewhich integrates a memory storing a communication control program, aprocessor executing this program, and associated circuits. The antennaswitch 964 switches connection of the antenna 965 between a plurality ofcircuits included in the wireless communication interface 963. Theantenna 965 includes a single or a plurality of antenna elements usedfor wireless signal transmission and reception via the wirelesscommunication interface 963.

The control unit 160 described with reference to FIG. 1 may be mountedon the wireless communication interface 963 in the wireless access point950 shown in FIG. 11. In addition, at least a part of the functions ofthe wireless access point 950 may be incorporated in the controller 951.

Note that the respective embodiments described above are presented byway of examples for realizing the present technology. Matters includedin the embodiments, and specific matters of the invention according tothe appended claims are correlated with each other. Similarly, thespecific matters of the invention according to the appended claims, andmatters to which identical names are given in the embodiments of thepresent technology are correlated with each other. However, the presenttechnology is not limited to the embodiments herein, but may be realizedwith various modifications of the embodiments without departing from thesubject matters of the embodiments.

In addition, the processing procedures described in the foregoingembodiments may be considered as a method including a series of theseprocedures, as a program under which a computer executes the series ofprocedures, or as a recording medium in which the program is stored. Therecording medium may be constituted by a compact disc (CD), a minidisc(MD), a digital versatile disc (DVD), a memory card, a Blu-ray(registered trademark) disc, or others.

Note that effects to be produced are not limited to the effectsdescribed in the present specification presented only by way of example.Additional effects may be also produced.

Note that the present technology may have following configurations.

(1)

An information processing device including:

a reception unit that receives a packet; and

a control unit that controls a packet monitoring state in case ofdetection of reception of a packet not addressed to the informationprocessing device, the packet monitoring state being controlled on thebasis of reception power of the packet.

(2)

The information processing device according to (1) described above, inwhich the control unit controls the packet monitoring state on the basisof a comparison result between the reception power of the packet notaddressed to the information processing device and a predeterminedthreshold.

(3)

The information processing device according to (2) described above, inwhich the control unit determines the threshold on the basis ofreception power of a reference signal received from a first device thattransmits a packet addressed to the information processing device.

(4)

The information processing device according to (3) described above, inwhich the control unit determines the threshold by using a latestreference signal included in reference signals received from the firstdevice, or a plurality of reference signals received from the firstdevice.

(5)

The information processing device according to (3) described above, inwhich the control unit determines the threshold by using a referencesignal that has lowest reception power, or a reference signal that hashighest reception power incase of presence of a plurality of the firstdevices.

(6)

The information processing device according to any one of (3) through(5) described above, in which the control unit determines the thresholdby using at least any one of a battery residual amount of theinformation processing device, a volume of data handled by theinformation processing device, a type of the data, and a communicationenvironment of the information processing device.

(7)

The information processing device according to anyone of (3) through (6)described above, in which the control unit updates the threshold forevery reception of the reference signal from the first device.

(8)

The information processing device according to any one of (3) through(6) described above, in which the control unit updates the threshold incase of detection of movement of the information processing device orthe first device.

(9)

The information processing device according to any one of (2) through(8) described above, in which the control unit brings the packetmonitoring state into a sleep state for a period specified on the basisof a size of the packet not addressed to the information processingdevice in a case where reception power of the packet not addressed tothe information processing device is high with respect to the threshold.

(10)

The information processing device according to (9) described above, inwhich the control unit brings the packet monitoring state into the sleepstate for at least a period until an end of the packet not addressed tothe information processing device.

(11)

The information processing device according to (9) described above, inwhich the control unit brings the packet monitoring state into the sleepstate for a period of a sum of a period until an end of the packet notaddressed to the information processing device and a predeterminedperiod.

(12)

The information processing device according to (11) described above, inwhich the predetermined period is a value that corresponds to any one ofshort inter frame space (short IFS) (SIFS), DCF IFS (DIFS), and atransmission period of a response signal for the packet not addressed tothe information processing device.

(13)

The information processing device according to any one of (10) through(12) described above, in which the control unit specifies the end of thepacket not addressed to the information processing device on the basisof length stored in a physical layer (PHY) header of the packet notaddressed to the information processing device.

(14)

The information processing device according to any one of (1) through(13) described above, in which the control unit detects the packet notaddressed to the information processing device on the basis of BasicService Set (BSS) Color contained in a PHY header of the receivedpacket.

(15)

The information processing device according to any one of (2) through(13) described above, in which the control unit notifies a first deviceabout the threshold, the first device transmitting a packet addressed tothe information processing device.

(16)

An information processing method including:

a detection procedure that detects reception of a packet not addressedto the information processing device; and

a control procedure that controls a packet monitoring state in case ofdetection of reception of a packet not addressed to the informationprocessing device, the packet monitoring state being controlled on thebasis of reception power of the packet.

(17)

A program under which a computer executes:

a detection procedure that detects reception of a packet not addressedto the information processing device; and

a control procedure that controls a packet monitoring state in case ofdetection of reception of a packet not addressed to the informationprocessing device, the packet monitoring state being controlled on thebasis of reception power of the packet.

REFERENCE SIGNS LIST

-   100, 201 to 203 Information processing device-   110 Data processing unit-   120 Signal processing unit-   130 Wireless interface unit-   140 Antenna-   150 Storage unit-   160 Control unit-   900 Smartphone-   901 Processor-   902 Memory-   903 Storage-   904 External connection interface-   906 Camera-   907 Sensor-   908 Microphone-   909 Input device-   910 Display device-   911 Speaker-   913 Wireless communication interface-   914 Antenna switch-   915 Antenna-   917 Bus-   918 Battery-   919 Auxiliary controller-   920 Car navigation device-   921 Processor-   922 Memory-   924 GPS module-   925 Sensor-   926 Data interface-   927 Content player-   928 Storage medium interface-   929 Input device-   930 Display device-   931 Speaker-   933 Wireless communication interface-   934 Antenna switch-   935 Antenna-   938 Battery-   941 In-vehicle network-   942 Vehicle module-   950 Wireless access point-   951 Controller-   952 Memory-   954 Input device-   955 Display device-   957 Network interface-   958 Wired communication network-   963 Wireless communication interface-   964 Antenna switch-   965 Antenna

The invention claimed is:
 1. An information processing devicecomprising: circuitry configured to acquire a predicted reception powerof packets addressed to the information processing device; determine asleep determination power threshold based on the predicted receptionpower; receive a packet; determine if the received packet is addressedto the information processing device on the basis of Basic Service Set(BSS) Color contained in a PHY header of the received packet; if thereceived packet is not addressed to the information processing device,determine if a reception power of the received packet exceeds the sleepdetermination power threshold; if the received packet is not addressedto the information processing device and if the reception power of thereceived packet exceeds the sleep determination power threshold, shiftthe information processing device to a sleep state; and if the receivedpacket is not addressed to the information processing device and if thereception power of the received packet does not exceed the sleepdetermination power threshold, shift the information processing deviceto a packet detection state.
 2. The information processing deviceaccording to claim 1, wherein the circuitry is further configured to ifthe received packet is addressed to the information processing device,shift the information processing device to a packet reception state. 3.The information processing device according to claim 1, wherein thecircuitry is further configured to determine the sleep determinationpower threshold on the basis of reception power of a reference signalreceived from a first device that transmits a packet addressed to theinformation processing device.
 4. The information processing deviceaccording to claim 1, wherein the circuitry is further configured todetermine the sleep determination power threshold by using a latestreference signal included in reference signals received from a firstdevice, or a plurality of reference signals received from the firstdevice.
 5. The information processing device according to claim 1,wherein the circuitry is further configured to determine the sleepdetermination power threshold by using a reference signal that haslowest reception power, or a reference signal that has highest receptionpower in case of presence of a plurality of first devices.
 6. Theinformation processing device according to claim 1, wherein thecircuitry is further configured to determine the sleep determinationpower threshold by using one or more of a battery residual amount of theinformation processing device, a volume of data handled by theinformation processing device, a type of the data, and a communicationenvironment of the information processing device.
 7. The informationprocessing device according to claim 1, wherein the circuitry is furtherconfigured to update the sleep determination power threshold for everyreception of a reference signal from a first device.
 8. The informationprocessing device according to claim 7, wherein the circuitry is furtherconfigured to update the sleep determination power threshold in case ofdetection of movement of the information processing device or the firstdevice.
 9. The information processing device according to claim 1,wherein the circuitry is further configured to when the informationprocessing device is shifted to the sleep state, it remains in the sleepstate until an end of the received packet.
 10. The informationprocessing device according to claim 9, wherein the circuitry is furtherconfigured to determine the end of the received packet not addressed tothe information processing device on the basis of a length stored in aphysical layer (PHY) header of the received packet not addressed to theinformation processing device.
 11. The information processing deviceaccording to claim 1, wherein the circuitry is further configured towhen the information processing device is shifted to the sleep state, itremains in the sleep state until an end of the received packet plus apredetermined time period.
 12. The information processing deviceaccording to claim 11, wherein the predetermined time period is a valuethat corresponds to any one of short inter frame space (short IFS)(SIFS), DCF IFS (DIFS), and a transmission period of a response signalfor the received packet not addressed to the information processingdevice.
 13. An information processing method implemented by circuitry inan information processing device, the method comprising: acquiring, bythe circuitry, a predicted reception power of packets addressed to theinformation processing device; determining a sleep determination powerthreshold based on the predicted reception power; receiving, by thecircuitry, a packet; determining if the received packet is addressed tothe information processing device on the basis of Basic Service Set(BSS) Color contained in a PHY header of the received packet; if thereceived packet is not addressed to the information processing device,determining if a reception power of the received packet exceeds thesleep determination power threshold; if the received packet is notaddressed to the information processing device and if the receptionpower of the received packet exceeds the sleep determination powerthreshold, shifting the information processing device to a sleep state;and if the received packet is not addressed to the informationprocessing device and if the reception power of the received packet doesnot exceed the sleep determination power threshold, shifting theinformation processing device to a packet detection state.
 14. Theinformation processing method according to claim 13, wherein the methodfurther comprises: if the received packet is addressed to theinformation processing device, shifting the information processingdevice to a packet reception state.